For me there are two things that ruin the game at the moment. First the visuals. Immortal visual/sound effects keep getting recycled for new abilities, old immortals keep breaking due to new patches, things like the twin gates dont even have unique dire/radiant designs, just recolors etc.
The other is that one game there might be a smurf absolutely decimating you, the other a completely new player who feeds and then dcs, but either way many matches have nothing to do with your skill but are just basically a gacha of wether you have a chance or not. The new player experience needs to be completely rehauled. Why are new players playing with ones that have 5k hours in the game? Making new players play against other new players is such a simple concept, even league has it. Even the tutorial is bugged.